FKC288 in Participants With Autoimmune Kidney Diseases

Inclusion Criteria:

1. Participants must personally sign an informed consent form approved by the EthicsCommittee before the start of the study.
2. Participants must be aged ≥18 and ≤65 years.
3. Disease-specific inclusion criteria: Active, relapsing, refractory Lupus Nephritis (LN): LN diagnosed by kidney biopsy within the last 2 years, with pathological types III,IV, or V, and a chronicity index (CI) score≤3 Meets one of the following criteria: Refractory LN, defined as no remission after at least one standard regimen (CTX and/orMMF) for 6 months. Relapsing LN, defined as a need to increase steroid dosage to control disease activityduring maintenance treatment. Clinical criteria: eGFR > 45 ml/min/1.73 m²; urinary protein quantification ≥ 1.5g/24h; SLE-DAI score ≥ 8. ANCA-associated vasculitis (AAV) patients: Diagnosed as AAV according to the 2012 Chapel Hill Consensus Conference criteria,meeting one of the following: Newly diagnosed AAV with renal involvement: Renal involvement must meet both: Kidney biopsy showing pauci-immune necrotizing glomerulonephritis. Urinary red bloodcells >30/high power field. Relapsing or refractory AAV: Relapse: Defined as an increase in BVAS V3.0 score of ≥1 after remission, requiringadjustment of immunosuppressive treatment to regain remission. Refractory: Defined as a) less than 50% reduction in BVAS V3.0 after 6 weeks ofstandard induction treatment; or b) persistent disease activity (BVAS V3.0 ≥3) after 12 weeks of treatment. Membranous nephropathy (MN) patients: Tissue biopsy diagnosed as aPLA2R-related membranous nephropathy. Clinical criteria for high-risk or relapsing/refractory membranous nephropathy: High-risk patients: Defined as meeting any of the following: eGFR normal, urinary protein >3.5g/d,ACEI/ARB treatment for 6 months with <50% reduction in urinary protein, combined withserum albumin <25g/l or aPLA2R >50RU/ml; or eGFR <60ml/min/1.73m², and/or urinaryprotein >8g/d for over 6 months. Refractory/relapsing membranous nephropathy patients: Refractory: Defined as resistance to previous immunosuppressive treatment (persistenturinary protein ≥3.5g/d with <50% reduction compared to baseline). Relapse: Defined as complete or partial remission achieved with previousimmunosuppressive treatment, followed by reappearance of urinary protein ≥3.5g/d. eGFR ≥ 45 ml/min/1.73 m². IgG4-related disease patients: Meeting the 2019 ACR/EULAR diagnostic criteria for IgG4-related disease, and meetingone of the following: Newly diagnosed active IgG4-related disease (Respond Index (RI) ≥3). Refractory or relapsed IgG4-related disease: Refractory: Defined as no remission with steroid or steroid plus immunosuppressanttreatment (no clinical or imaging improvement, RI decrease <2) Relapse: Defined as newprogression or recurrence of clinical symptoms or imaging findings in a patient whohad achieved remission, with or without elevated blood IgG4 (RI increase≥2)
4. Expected survival ≥ 12 weeks.
5. ECOG performance status ≤ 2.
6. Female participants of childbearing potential must agree to use effectivecontraception from the day of signing the informed consent until 365 days after theinfusion. Effective contraception is defined as abstinence or the use of acontraceptive method with a failure rate of <1% per year.
7. Participants must have adequate organ function, meeting all of the following criteriabefore enrollment:
8. Absolute neutrophil count ≥ 1.0×10⁹/L [Granulocyte colony-stimulating factor (G-CSF) support is allowed, but no supportive treatment should be received within 7 days before the assessment].
9. Platelet count ≥ 50×10⁹/L [No transfusion support (including componenttransfusion) or treatments aimed

Exclusion Criteria:

1. Participants who have received the following previous treatments: 1.1 Participants who have received gene therapy before enrollment. 1.2 Participantswho have been injected with live vaccines within 4 weeks prior to enrollment. 1.3 Participants who have received other investigational drug treatments within 12weeks before apheresis.
2. Participants with active malignancies within the past 5 years, except for tumorsdeemed curable and cured, such as basal or squamous cell carcinoma, cervical or breastcarcinoma in situ, etc.
3. Participants who are positive for Hepatitis B surface antigen (HBsAg) or Hepatitis Bcore antibody (HBcAb) with abnormal peripheral blood HBV DNA tests (defined as HBV DNAquantification above the lower limit of detection or above the normal reference rangeof the testing center, or qualitative HBV DNA test positive); positive for Hepatitis Cvirus (HCV) antibodies with positive peripheral blood HCV RNA; positive for HumanImmunodeficiency Virus (HIV) antibodies; positive for Cytomegalovirus (CMV) DNA;positive for syphilis test RPR.
4. Participants with uncontrolled active infections (except for < Grade 2 CTCAE urinaryreproductive system infections and upper respiratory infections).
5. Participants with severe heart diseases, including but not limited to unstable angina,myocardial infarction (within 6 months prior to screening), congestive heart failure (New York Heart Association [NYHA] class ≥ III), severe arrhythmias.
6. Participants with hypertension or diabetes that cannot be controlled with medication.
7. Participants with unresolved toxic reactions from previous treatments to baseline or ≤Grade 1 (according to NCI-CTCAE v5.0, except for alopecia and clinically insignificantlab abnormalities).
8. Participants who have undergone major surgery within 2 weeks prior to enrollment orplan to have surgery during the waiting period for infusion or within 12 weeks afterreceiving study treatment (except for planned minor surgeries under local anesthesia).
9. Participants with solid organ transplants.
10. Pregnant or breastfeeding women.
11. Participants with a history of central nervous system diseases (such as cerebralaneurysm, epilepsy, stroke, dementia, psychosis, etc.) or consciousness disorders.
12. Participants with other unstable systemic diseases as judged by the researcher,including but not limited to severe diseases of the liver, kidneys, gastrointestinaltract, or metabolic diseases requiring medication.
13. Participants are known to have life-threatening allergic reactions, hypersensitivity,or intolerance to FKC288 cellular products or their components.
14. Participants judged by the researcher to have bleeding, severe thrombosis, orhereditary/acquired bleeding and severe thrombosis conditions (including hemophilia,coagulation dysfunction, thrombocytopenia, splenomegaly, etc.), or patients currentlyundergoing thrombolytic or anticoagulant therapy.
15. Participants who have received any B cell-depleting therapy or non-depleting B celltargeted therapy within 6 months.
16. Participants who have received high-dose methylprednisolone treatment (cumulative dose > 1.5g) or cyclophosphamide pulse therapy within a month.
17. Participants judged by the researcher to be unable to discontinue otherimmunosuppressants one week before apheresis, or those treated with more than 5 mg/dayof prednisone (or equivalent dose of other corticosteroids).
18. AAV patients diagnosed with eosinophilic granulomatosis with polyangiitis (formerlyChurg-Strauss syndrome) or with active alveolar hemorrhage.
19. Other conditions deemed by the researcher as unsuitable for enrollment.